2.6. Statistical analysis
The mean plate counts of the treated samples (N) were divided
by the average control plate counts (No) to give a survivor ratio (N/
No). The log10 (N/No) of the ratios was then used for determination
of D10-values and other statistical analyses. D10-values were
determined by the reciprocal of the slope following linear regression
as determined by least squares analysis (Diehl, 1995). Each
experiment (D10 determination) was conducted independently
three times. A minimum of 5 time points were used for determination
of D10. Statistical analysis functions of MS Excel (Microsoft
Corp., Redmond, WA) were used for routine calculations (D10
determination), descriptive statistics, two way analysis of variance
(ANOVA, 95% confidence).